title: Cardiac channelopathies associated with infantile fatal ventricular arrhythmias: from the cradle to the bench.
abstract: BACKGROUND
  Fatal ventricular arrhythmias in the early period of life have been associated with cardiac channelopathies for decades, and postmortem analyses in SIDS victims have provided evidence of this association. However, the prevalence and functional properties of cardiac ion channel mutations in infantile fatal arrhythmia cases are not clear.
  
  
  RESULTS
  Seven infants with potentially lethal arrhythmias at age < 1 year (5 males, age of onset 44.1 ± 72.1 days) were genetically analyzed for KCNQ1, KCNH2, KCNE1-5, KCNJ2, SCN5A, GJA5, and CALM1 by using denaturing high-performance liquid chromatography and direct sequencing. Whole-cell currents of wildtype and mutant channels were recorded and analyzed in Chinese hamster ovary cells transfected with SCN5A and KCNH2 cDNA. In 5 of 7 patients, we identified 4 mutations (p.N1774D, p.T290fsX53, p.F1486del and p.N406K) in SCN5A, and 1 mutation (p.G628D) in KCNH2. N1774D, F1486del, and N406K in SCN5A displayed tetrodotoxin-sensitive persistent late Na(+) currents. By contrast, SCN5A-T290fsX53 was nonfunctional. KCNH2-G628D exhibited loss of channel function.
  
  
  CONCLUSIONS
  Genetic screening of 7 patients was used to demonstrate the high prevalence of cardiac channelopathies. Functional assays revealed both gain and loss of channel function in SCN5A mutations, as well as loss of function associated with the KCNH2 mutation.
authors.affiliation: Department of Cardiovascular and Respiratory Medicine, Shiga University of Medical Science, Shiga, Japan.
authors.forename: Koichi
authors.initials: K
authors.lastname: Kato
authors.forename: Takeru
authors.initials: T
authors.lastname: Makiyama
authors.forename: Jie
authors.initials: J
authors.lastname: Wu
authors.forename: Wei-Guang
authors.initials: WG
authors.lastname: Ding
authors.forename: Hiromi
authors.initials: H
authors.lastname: Kimura
authors.forename: Nobu
authors.initials: N
authors.lastname: Naiki
authors.forename: Seiko
authors.initials: S
authors.lastname: Ohno
authors.forename: Hideki
authors.initials: H
authors.lastname: Itoh
authors.forename: Toshio
authors.initials: T
authors.lastname: Nakanishi
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Matsuura
authors.forename: Minoru
authors.initials: M
authors.lastname: Horie
mesh_terms: D000818:Animals; D001145:Arrhythmias, Cardiac / Q000150:complications / Q000175:diagnosis / Q000235:genetics; D053840:Brugada Syndrome; D000075224:Cardiac Conduction System Disease; D053447:Channelopathies / Q000150:complications / Q000175:diagnosis* / Q000235:genetics*; D006224:Cricetinae; D000072237:ERG1 Potassium Channel; D051638:Ether-A-Go-Go Potassium Channels / Q000235:genetics*; D017809:Fatal Outcome; D005260:Female; D006329:Heart Conduction System / Q000002:abnormalities; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D009154:Mutation / Q000235:genetics; D062554:NAV1.5 Voltage-Gated Sodium Channel / Q000235:genetics*; D010375:Pedigree; D017180:Tachycardia, Ventricular / Q000150:complications / Q000175:diagnosis* / Q000235:genetics*
chemical_list: D000072237:ERG1 Potassium Channel; D051638:Ether-A-Go-Go Potassium Channels; C000606913:KCNH2 protein, human; D062554:NAV1.5 Voltage-Gated Sodium Channel; C568320:SCN5A protein, human
keywords: Brugada syndrome; KCNH2; SCN5A; SIDS; long-QT syndrome; ventricular arrhythmia